#mask_box{
    position: absolute;
    width: 100vw;
    height: 100vh;
    background: rgba(0, 0, 0, 0.678);
    z-index: 9999999;
}

#close_btn{
    position: absolute;
    top: 10px;
    right: 10px;
    width: 40px;
    height: 40px;
    border: 1px solid blue;
    border-radius: 30px;
    text-align: center;
}

#close_btn button{
    line-height: 40px;
    cursor: pointer;
    background: none;
    border: none;
    font-size: 24px;
    color: white;
}